There are many approaches that the industry uses to make optical splitters. One approach is a fused pair element design, where an input optical fiber(s) is chemically or sonically welded to a number of output optical fibers. The output optical fibers are usually wrapped around a central input optical fiber(s). Light from the input optical fiber(s) reaches the fused section, and ideally an equal portion of light is coupled to each of the output optical fibers. The fused pair approach is very difficult to mass produce and, as the number of output optical fibers increases, the uniformity decreases [due to the fact that those optical fibers closer to the center of the fused element (input optical fiber(s)) receive more of the light].
A second optical splitter design approach is to use a separate mixing element. Light from a single input optical fiber is coupled to a larger fiber optic ribbon mixing element. By the time the light reaches an output side of the ribbon mixing element, the light is ideally spread evenly across an endface of the fiber optic ribbon mixing element so that an even amount is coupled to each of the output optical fibers. An example of the second noted approach is shown in U.S. Pat. No. 4,995,692. However, applying the second approach requires use of a 32 mm by 0.9 mm ribbon mixing element to split the optical signal into 32 output signals. An input optical fiber 11 one millimeter in diameter is placed in the middle of an input side of the ribbon mixing element 13, and the various output optical fibers 23 are aligned along an output face of the ribbon mixing element 13 (see FIG. 2). There are several problems with the second approach. In order to get the light to spread evenly across the endface 123 of the ribbon mixing element 13 (to assure good uniformity), the ribbon mixing element length 17 is increased significantly, making the package size of the ribbon mixing element 13 very large. Secondly, increasing the length of the ribbon mixing element 13 also increases the attenuation experienced inside the ribbon mixing element 13, increasing the total insertion loss of the optical splitter 9.